It is known to provide a piece of machinery with an automatic lubricant dispenser that is pressurized to force a fluent lubricant, normally an oil or grease, along a conduit into a part, typically a bearing, of the machine. In order to avoid having to provide a pump it has been suggested to provide a gas-generating cell which pressurizes the lubricant by means of a chemical reaction that can be initiated by the user when the dispenser is connected to the machine, and that generates sufficient gas to deplete the entire supply of lubricant in the dispenser.
In German patent 3,718,341 filed 01 Jun. 1987 by B. Jorissen a vessel is internally subdivided by a piston into a lower compartment adapted to hold a supply of a fluent lubricant and an upper compartment. The lower side of the supply is formed with an outlet adapted to be connected via a conduit to a machine to be lubricated. The upper compartment is provided with an anode and cathode in an electrolyte so that when current passes between them the electrolyte generates gas and the piston is pushed down, pressurizing the lubricant in the lower compartment. Obviously this is a fairly complex device.
German patent document 3,811,469 filed 6 Apr. 1988 also by B. Jorissen describes another such system where the vessel containing the lubricant is fitted with a complete gas-generating cell comprising a compartment containing a reactive liquid and a cartridge defining a compartment containing an active-alloy metal that can react with the liquid to generate a gas. The cartridge is screwed into the cell to activate the chemical reaction and drive down a separate piston that is provided in the vessel. Once again this system is fairly complex.